The use of computer assisted surgery systems (CAS systems) or image guided surgery systems is becoming widespread. In a typical CAS system, a computer and a position measurement device are used in order to measure the position of surgical instruments, devices and a body portion of the patient. CAS systems also incorporate a memory means to store medical data such as e.g. X-rays, computertomographs or magnetic resonance images (MRIs). The medical images may be gathered pre-operatively or intraoperatively.
Computer assisted orthopaedic surgery systems include a) computeltomogram (CT) based systems, may be used preoperatively to establish a three-dimensional anatomical model of a bone or bone fragment that is referenced during the surgical procedure to identify the respective bone or bone fragment through a landmark based or surface based registration or matching procedure; b) CT based and fluoroscopy systems, which use the same method as CT based systems to establish a three-dimensional anatomical model, whereby the preoperative CT of a bone or bone fragment is registered or matched to the intraoperative respective bone or bone fragment through using a surface model of the bone or bone fragment and its projections in the planes of the fluoroscopic images; and c) fluoroscopy based systems, which use calibrated fluoroscopes to generate undistorted images of a bone or bone fragment and virtual geometric representations of the projection of surgical tools.
When used during a surgical procedure, most CAS systems require input from the surgeon in order to specify the data to be shown or to alter the program flow. The surgical data may include data stored preoperatively as well as data obtained during the surgery, such as blood pressure, heart rate, oxygen levels, etc. Many systems rely upon a non-sterile assistant to input instructions at a keyboard or with a mouse, but these systems are inefficient and risk miscommunication.
In other systems, an input device is physically located within the operating room. The input device is generally covered with a plastic material to provide a physical barrier against the spread of germs. When control of the CAS is required, the surgeon or other personnel within the operating room go to the location of the input device and operate the device. This approach is cumbersome since it requires a dedicated location for the input device within an already crowded operating room. Moreover, the movement of personnel to the location of the input device creates undesired activity within the operating room.
Some systems have attempted to address the shortcomings of the above described approach in various ways. One such approach is to provide an input device in the form of a foot operated device. Of course, this type of a device becomes a hazard when personnel are moving about the location of the foot operated device. Moreover, the foot operated devices do not provide for cursor control.
What is needed, therefore, is a CAS input device that allows personnel to control the CAS during an operation.
What is further needed is a CAS input device that does not require personnel to move to a specific location within the operating room to operate the device.
What is also needed is a CAS input device that is conveniently located for ease of access and which allows for the control of the cursor on a display.
What is needed is a CAS input device that does not present a hazard to individuals moving about an operating room.